Medical, dental, pharmaceutical, veterinary or mortuary instruments and devices that are exposed to blood or other body fluids require thorough cleaning and anti-microbial deactivation or sterilization between each use. Liquid microbial deactivation systems are now widely used to clean and deactivate instruments and devices that cannot withstand the high temperatures of a steam sterilization system. Liquid microbial deactivation systems typically operate by exposing the medical devices and/or instruments to a liquid disinfectant or sterilization composition, such as peracetic acid or some other strong oxidant.
In such systems, the instruments or devices to be cleaned are typically placed within a chamber within the liquid microbial deactivation system, or in a container that is placed within the chamber. A liquid disinfectant is then circulated through a liquid circulation system that includes the chamber (and the container therein) during a sterilization or microbial deactivation cycle.
The circulation system typically includes an air purge/fluid overflow assembly to allow air to be purged from the system during the filling of the circulation system. A “make-up” air system is also provided to allow air to enter the circulation system when the liquid deactivation fluid is drained therefrom.
A problem with such air purge/fluid overflow assembly and air make-up assemblies is preventing biological contaminants from entering the chamber (and container) when external air is drawn into the chamber after a sterilization or deactivation cycle. With respect to the air make-up assembly, it is known to use a HEPA-grade filter to filter the incoming air, but the filtering of the incoming air does not insure sterile conditions exist in the conduit or line connecting the filter to the chamber.
The present invention overcomes these and other problems and provides a combination fluid over-flow block/make-up air assembly that maintains sterile or microbially deactivated conditions between a make-up air filter and the chamber in a liquid sterilization or microbial deactivation system.